Cooling power unit



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nal combustion apparatus. generators and motors'arewell known. Fans forbearings, of thesetmachines.

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Patented May 2, 1950 UNH.El) STATES Rei'iENT OFFICE COOLING POWER UNIT`ClarenceF. Schwan, Warrensville Heights, Ohio, "assignor to The OhioCrankshaft Company,

Cleveland, Ghio, alcorporation of..0hio

Application yNovember 13, 1946, Serial No. 709,643

(Cl. Fil-252) 3 Claims. l

VThe'present' invention relates as indicated to inearls` and vmethodfoi" cooling' power.' units and fis" directed .primarily tocoolingrotary type electric generators and motors, but withmodifications itis adapted for use' in cooling other apparatus such as.transformers and high frequency oscillator tubes. It is' adaptable alsoto the cool- Ing of .power unitssuch as some formsof inter- Means forcooling circulating air through such machines have been employed formany years. The circulation of water' through parts oi generatorsand'motors for absorbing heat generated in various parts ol suchmachines has also beenknown and employed. Howeventhecombination of suchair 'and Water cooling possesses. advantag.esv which have not been`generally recognized; In co-penfing application Serial. No: 548,084,nled August 4," 1944', noW'Patent-No. 2,466,007, by F. S?. Den- .n'eenand'` W.' C. Dunnand owned by the assignee of the present application,oneform of'su'ch combination of cooling meansy has been shown anddescribed. In the apparatus of'v that application; external heattransfer means haveA been employed. The present invention'isanimprovement on themeans and. method shown and described' in thatapplication in that such external transfer'means is notrequired.

Veryfrequently it is found necessary to operatemotors, generators .andother machines in atmospheres ofi harmful vapors or'airfiilled withmachines interfering with their normal cooling and operation, butparticles of the" dust are irel 'quently abrasive andseriously' damageparts, such Also. the insulating. elect of Vlayers of'du'st -Whichcollect on surfaces of interior parts of such machines interferes withthe normal iiow and dissipation oi heat from parts. in.. which heatv isgenerated. Suchv machines when.. operated.. at substantially full loadheat rapidly and soon attainy harmful temperatures. Usually,` asthetemperature rises unequal expansions occur resulting in reduced -ai-rgapclearances. The change in output and vol-tageeaused by decreasedairfgaps cause serious .power iiuctuations and a very harmfulreductionin-.the over-all performance ofthemachine.

n viewofthe above Aconditions it has been an `object or the presentinvention to yprovide means fior.. cooling internal parts of. electric.machines wh'icliithas not 'been able .to cool efoiently here- One oi.the objects of this .invention has been to equalize temperatures so asto control .air

lgapand other clearances and'thus to reduce the size ofsuch machines andthe amount of material'. required.. in their construction. Anotherobject` has. been .to provide. means -.for .operating Avsuoli machinesat lower temperatures than it was possible to operate them heretofore.An` additional object has been to provideiiuid circulating means inwhich the amount of fluid required is greatly reduced. A further objecthas been to provide means for the rapid and direct transfer of heat fromheated parts to the cooling fluid. Another object has been to provide astructure adaptable to change for controlling a rate of cooling orn aninner part of such apparatus. lA further object has been to provide astructure in which parts are readily proportioned to provide maximumcooling with minimum reluctance in magneticcircuits of the mechanism.A'still further object has been to provide means for localizing andremoving accumulations of foreign'partlcles ,from the liquid in themachines. An additional object has been to provide a method'of coolingpower generating or transforming apparatus which is applicable generallyto all such apparatus.

A more specific object of 'the invention is the provision of new andimproved rotary electrical apparatus including a rotor and a statorabout the rotor, the stator including laminations with acircnmierentially-extending cooling-medium passage about the laminationsand longitudinally-extending cooling-medium passages exteriorly of thecrcumferentially-extending passage.

Still a further obect is new and improved iotor electrical apparatus ofthev type comprising a rotor and a stator, the stator comprisinglaminations about the rotor, a shell supporting the laminations andhaving a passage extending substantially the full circumferential lengthof the shell about the lamnations and a housing surrounding the shelland in spaced relationship thereto to forni longitudinally-extendlngcooling-medium passages over generally the entire length of the stator.

With these and other objects in view, this invention then consists ofthe general method of cooling power generating and transmittingequipment together with the apparatus used in the practice oi thismethod.

To provide a better understanding of this invention, one form of it ishereinafter explained, reference being had to the accompanying drawings.

In thev drawings:

Fig. 1 is a. longitudinal elevation partly in sectiontaken at l-i ofFig. 2.

prises shaft l2 to which bars I4 are attached, usually by welding, whichbars are machined to accurately support laminated cores I6 in concentricrelation with the shaft, the laminations being rmly compressed betweenshaft ring il and ring nut I8 which engages threads cut on the ends ofbar E4. These laminations have teeth or slots I9 cut in their outerperipheries. The stator comprises frame members 2li and 2i held inconcentric relation by pilot 22 and with annular surfaces abutting at 24to close the exterior part of a magnetic circuit which is provided -byannular eld coil 25 lying in the annular space 26 between interior partsof members 20 and 2l. Members 2E! and 2i are bored to receive two groupsof laminations 28 and 29 in close heat conducting engagement. Thelaminations are held firmly in place and clamped together by rings suchas Se and 35. After assembly stator laminations 28 and 29 are so boredand rotor laminations I6 are so turned that the rotor rotates in thestator with a very limited clearance, the rotor being accuratelysupported on anti-friction bearings such as 32 carried in bearingsupports 33 oi the stator frame members. Windings 34 in which highfrequency current is generated are set in slots in the inner peripheryof the stator laminations and are provided with leads extending througha side wall of the generator housing.

Considerable heat is generated by hysteresis and eddy currents in bothrotor and stator, and means are provided to cool both of these parts. Itwill be obvious that liquids, which are usually more effective coolingagents than gases, cannot readily be brought into heat conductingcontact with all parts, such as parts of the rotor, and that gases mustbe employed to pick up the heat from these rotor parts and transfer itto other parts of the machine where it is conducted into cooling liquidor is carried away by exterior radiation. It will be observed that thegenerator shown in Figs. l, 2 and 3 above described, possesses therequired elements for such removal of heat. Suhl- -cient air, hydrogenor other gas at desired pressure is usually confined within the outerwalls of the generator and is circulated in generally axial directionsby blower or fan 35 whose rotating member is attached to shaft l2 eitherdirectly or is secured to the ends of bars ill as shown. When the shaftis turning at normal speed, the vanes 3l of the fan by centrifugal forcethrow the air radially outward in the blower casing 38, the inlet tothis casing being passages 3d between bars le and holes 4t which passentirely through laminated cores i6. Some air also passes through theannular clearance space 42 between rotor and stator. This air, by thuspassing axially through the interior, over the exterior', and throughthe passages in the laminated cores i6 or the rotor, comes intoeffective heat transferring relation with this core and heat generatedin the core is rapidly absorbed by the air. rilhis heated air is thencooled by flowing it through passages i4 which extend axially throughopposite sides or the stator. In traversing these passages the air comesinto contact with outer wall or cover 45 through which soine heat flowsfrom the heated air into the outside atmosphere. Most of the heat whichhas been picked up by the air in passing through and over the rotorcore, however, is absorbed by wall fins t9 generally integral therewithgreatly increasing the heat absorbing area of this wall. The heatabsorbed by this iinned wall is rapidly transferred to water passingthrough annular jacket 50, the nned wall forming a partition between theouter air passage and the water jacket. By selecting longer, thinner andmore numerous fins the heat absorbing surface may be increased to anydesired degree and by controlling temperatures of the water or otherfluid owing through the jacket the temperature of the air being returnedto the rotor is reduced to any desired degree.

The water in passing through jacket 5G not only absorbs heat from wall53 through which it is conducted from the air in passage 44, but thiswater rapidly absorbs heat produced in the stator core 29. rIhis core,being tightly iitted into the bore of the housing is in excellent heatconducting contact with they inner housing wall into which its heat israpidly transferred and from which it is absorbed by the water in jacket50. rlhe water in this jacket may circulate in various directions suchas axially, circumferentially or helically. Fig. 2 shows means for acircumferential iiow of the water. A sediment trap 52 is shown at thebottom of the jacket where dirt collects which otherwise might obstructthe flow of the water or adhere to surfaces of the jacket wall andretard the transfer of heat to the jacket water.

In Fig. 2 the cooling air passes through opposite sides of stator frame.A more uniform distribution of air is obtained in the arrangement shownin Fig. Il. The fan or blower draws air through the rotor insubstantially the same way as is shown in Figs. l, 2 and 3, but it isdelivered so as to flow axially through outer passages such as 60 in thestator frame forming a substantially com plete cylindrical streamsubstantially equally distributing its cooling effect throughout theperiphery of the stator. Spacing members 6| serve as means for locatingthe core supporting ring 62 within the frame. Inlet and outlet passages64' and 65 for cooling water are placed adjacent to each other at thetop of the stator, being separated by a partition E5 to insure asubstantially complete peripheral circuit for the water in the spacebetween the outer air jacket and the inner core support ring G2. Meansfor drawing off accumulations or sediment is provided at the lower partof the water jacket as indicated at 68.

Numerous modications can be made in the construction of the generatorillustrated. For instance, bars i4 can be omitted and the laminations ofcore IS can be attached directly to shaft i2 and additlonal passagessimilar to holes 4U provided for the flow of additional cooling fluid.Also shaft l2 can be made of tubular or other hollow construction toprovide a passage for additional cooling medium or to serve as means fordistributing the cooling medium to various parts of the apparatus.

In the construction shown fan 31 is so made and passages 39 and 4Q areso selected as to size and location as to control the amount of air orother gas passing 'through rotor it. The size of the rotor coresupporting ribs i4 is so proportioned as to not only oier the necessaryarea for cooling air passages 39 lying between adjacent ribs, but theseribs are large enough to serve eiciently as a part of the magneticcircuit passing through the rotor core. The control provided by the fanand by the rotor passages, in combination with valve means forcontrolling the amount of water or other liquid passing through jacket55B and the temperature of that liquid, readily so regulates therelative temperatures of rotor and stator that the temperature of one ismaintained at a substantially definite preselected value relative to theother. By this means thermal expansion of rotor and stator are socontrolled that air gap 42 is maintained constant or in some cases isreduced to a prescribed amount as the temperatures of rotor and statorrise to maximum values. As the air `gap decreases to a prescribedminimum, the outputr and efliciency of the generator both tend toincrease, the temperatures being controlled, however, by thecirculations of the cooling iluidsso that suicient operating clearancebetween rotor and stator is always maintained.

It will be' apparent to those Askilled in the art that many.l changes inthe method of cooling heatgenerating apparatus and variousmodicacumferential length of said shell, means for cir- 1;

culating a cooling medium circumferentially through said passage, saidstator also including a housing substantially surrounding said shell andin spaced relationship `.thereto and means for iii circulating a coolingmedium rlongitudinally of 5.

and a shell supporting said laminations, a pasif;

sage in said shell extending substantially the full circumferentiallength of said shell, means for circulating a cooling mediumcircumferentially through said passage, said stator also including ahousing surrounding said shell and in spaced relationship thereto, saidshell having a plurality cf longitudinally-extending fins extending intosaid space and means for circulating air longitudinally through saidspace and over said fins.

3. In rotary electrical apparatus, a rotor, a stator comprisinglaminations about said rotor and a shell supporting said laminations, apassage in said shell extending substantially the full circumferentiallength of said shell, means for circulating a cooling mediumcircumferentially through said passage, said stator also including ahousing surrounding said shell and in spaced relationship thereto andmeans for circulating a cooling medium longitudinally of said statorthrough the space between said housing and said shell, said passagehaving a sediment trap extending substantially throughout its axiallength positioned at the lower most point thereof.

CLARENCE F. SCHWAN.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 716,278 Reist Dec. 16, 19021,733,179 Baumann Oct. 29, 1929 2,220,032 Winther Oct. 29, 19402,306,582 Winther Dec. 29, 1942 2,414,532 Johns Jan. 21, 1947 FOREIGNPATENTS Number Country Date 37.816 Austria July 10, 1909 684,240 FranceMar. 17, 1930

